Mucuna laticifera: unprecedented L-dopa content and its role in neurodegenerative and inflammatory conditions.

Genus Mucuna encompasses several plant species renowned for their utilization in traditional Ayurvedic medicine for the treatment of Parkinson's disease, chiefly due to their exceptionally high L-dopa content relative to other plants. However, limited information exists regarding Mucuna laticifera, a newly identified species within the Mucuna genus. This study unveils a remarkable L-dopa content of 174.3 mg/g in M. laticifera seeds, surpassing all previously documented Mucuna species. Moreover, this research marks the first documentation of L-dopa, flavonoids, and phenolics within M. laticifera seeds. Furthermore, the aqueous extract derived from these seeds exhibits robust antioxidant properties. Investigation into its anti-inflammatory potential reveals a significant reduction in paw swelling and neutrophil infiltration at inflammatory sites in a carrageenan-induced rat model. Gene expression analysis utilizing a rat paw model demonstrates that the seed extract significantly downregulates the expression of various inflammation-related genes compared to carrageenan-treated rats. Collectively, these findings clearly substantiate the anti-inflammatory activity of M. laticifera seed extract. The exceptional L-dopa content combined with its anti-inflammatory properties position M. laticifera seeds as a promising therapeutic option for neurodegenerative diseases like Parkinson's, as well as various inflammatory conditions. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-024-03969-w.

Elucidating the efficacy of functionalized multi-walled carbon nanotube in the biogenesis of L-Dopa and antioxidant metabolites in cell cultures of Hybanthus enneaspermus.

Hybanthus enneaspermus (L.)F.Muell. is a highly indispensable medicinal herb yielding L-Dopa, deemed the gold standard drug among the therapeutic options for Parkinson's disease. This investigation is the first attempt to evaluate the eliciting influence of carboxylic acid functionalized multi-walled carbon nanotube (MWCNT-COOH) on the biosynthesis of L-Dopa and on biomass aggregation and antioxidant metabolites in H. enneaspermus cell suspension cultures. Suspension cells were accomplished from friable calli generated from the nodal segments of H. enneaspermus in Murashige and Skoog (MS) liquid medium infused with 2 mg L-1 2, 4-Dichlorophenoxyacetic acid (2, 4-D), and 0.3 mg L-1meta-Topolin (mT). The influence of MWCNTs on L-Dopa synthesis, biomass accumulation, and biochemical parameters was examined on the basis of the exposure time and in a concentration-dependent manner of MWCNTs. The inclusion of 30 mg L-1 MWCNTs increased the biomass and the L-Dopa level by 2.00 and 16.37-folds, respectively, compared with that of the control. Furthermore, the effect of MWCNTs on physiological parameters such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), ascorbate peroxidase (APX), hydrogen peroxide (H2O2), malondialdehyde (MDA) content, 2-diphenylpicrylhydrazyl (DPPH), and ferric-reducing ability of plasma (FRAP) was examined over the elicited cells. Among the antioxidant enzymatic activities, CAT enhanced 8.0 fold compared with that of the control. MDA and DPPH content enhanced 2.60 and 1.12 folds, respectively, compared with that of the control. The current study showed that MWCNTs offer new possibilities for their usage over in vitro by acting as potential innovative plant metabolite elicitors and stress-protecting entities.

Transcriptomic and metabolomic analyses reveal that lemon extract prolongs Drosophila lifespan by affecting metabolism.

Ageing is an evolutionarily conserved and irreversible biological process in different species. Numerous studies have reported that taking medicine is an effective approach to slow ageing. Lemon extract (LE) is a natural extract of lemon fruit that contains a variety of bioactive phytochemicals. Various forms of LE have been shown to play a role in anti-ageing and improving ageing-related diseases. However, studies on the molecular mechanism of LE in Drosophila ageing have not been reported. In this study, we found that 0.05 g/L LE could significantly extend Drosophila lifespan and greatly improve antioxidative and anti-heat stress abilities. Furthermore, transcriptome and metabolome analyses of 10 d flies between the LE-fed and control groups suggested that the differentially expressed gene ppo1 (Prophenoloxidase 1) and metabolite L-DOPA (Levodopa) were co-enriched in the tyrosine metabolism pathway. Overall, our results indicate that affecting metabolism was the main reason for LE extending Drosophila lifespan.

L-DOPA-therapy in Parkinson's disease: some personal reflections on L-DOPA therapy from Vienna and Berlin.

Dopamine was initially considered as a mere intermediate in the noradrenaline synthesis but was then found to be a neurotransmitter. Its depletion resulted in characteristic symptoms in experimental studies and could be antagonized by DOPA (3,4-dihydroxyphenylalanin), suggesting a similarity to the human disorder Parkinson´s disease (PD) and a therapeutic potential which was successfully exploited from the 1970s on. This was due to the pioneering work of Arvid Carlsson and clinicians around the world who first worked on the breakthrough of L-DOPA therapy and then on its amendment and modification and on alternative therapies for PD patients. All these developments led to the establishment of PD therapy as we know it today. It is characterized by the availability of many different compounds which are mostly employed in combination and by different methods: orally, intravenously, transdermally, subcutaneously, or duodenally. Here, we present without claim of completeness some personal reflections about causal drug developments for PD patients and reflect on some personal interactions with leading clinicians and basic researchers who cooperated with us. Such interactions are crucial for the creation, sometimes serendipitously, of fresh ideas and to further develop existing concepts to make therapeutical progress.

Metabolic Pathway Reconstruction Indicates the Presence of Important Medicinal Compounds in Coffea Such as L-DOPA.

The use of transcriptomic data to make inferences about plant metabolomes is a useful tool to help the discovery of important compounds in the available biodiversity. To unveil previously undiscovered metabolites of Coffea, of phytotherapeutic and economic value, we employed 24 RNAseq libraries. These libraries were sequenced from leaves exposed to a diverse range of environmental conditions. Subsequently, the data were meticulously processed to create models of putative metabolic networks, which shed light on the production of potential natural compounds of significant interest. Then, we selected one of the predicted compounds, the L-3,4-dihydroxyphenylalanine (L-DOPA), to be analyzed by LC-MS/MS using three biological replicates of flowers, leaves, and fruits from Coffea arabica and Coffea canephora. We were able to identify metabolic pathways responsible for producing several compounds of economic importance. One of the identified pathways involved in isoquinoline alkaloid biosynthesis was found to be active and producing L-DOPA, which is a common product of POLYPHENOL OXIDASES (PPOs, EC 1.14.18.1 and EC 1.10.3.1). We show that coffee plants are a natural source of L-DOPA, a widely used medicine for treatment of the human neurodegenerative condition called Parkinson's disease. In addition, dozens of other compounds with medicinal significance were predicted as potential natural coffee products. By further refining analytical chemistry techniques, it will be possible to enhance the characterization of coffee metabolites, enabling a deeper understanding of their properties and potential applications in medicine.

Curcumin modulation of L-dopa and rasagiline-induced neuroprotection in rotenone model of Parkinson's disease.

Objectives: Parkinson's disease (PD) is one of the most incurable, chronic, and progressive neurodegenerative disorders Worldwide. Curcumin, a natural polyphenolic anti-oxidant compound, has a long history in traditional medicine. We investigate the effect of curcumin on brain oxidative stress, DNA fragmentation, and motor changes in rotenone-induced PD in mice. The possible modulation of the anti-parkinsonian action of drugs L-dopa and rasagiline by curcumin was also studied. Materials and Methods: Mice received rotenone 1.5 mg/kg and were treated with curcumin (150 mg/kg), L-dopa (25 mg/kg), rasagiline (1 mg/kg), L-dopa+curcumin, or rasagiline+curcumin. Striatal malondialdehyde, reduced glutathione, nitric oxide, tyrosine hydroxylase, and brain DNA fragmentations were measured. Histopathological examination of brain tissues was done. Motor coordination and behavioral tests such as wire-hanging, stair, and wood-waking tests were included. Results: Rotenone caused elevation in brain malondialdehyde and nitric oxide contents, depletion of reduced glutathione accompanied by a reduction in rearing behavior, and impairment of motor activity in wire-hanging, stair, and wood-waking tests. Also, severe DNA fragmentation in the striatum, marked decrease of substantia nigra pigmented neurons, neuronal degeneration in the cerebral cortex and hippocampus, decreased glial fibrillary acidic protein reaction (GFAP) and glial cell size in the cerebral cortex were caused by rotenone. In rotenone-treated mice, brain oxidative stress was decreased by curcumin, L-dopa, rasagiline, curcumin+L-dopa, and curcumin+rasagiline. These treatments also prevented DNA fragmentation and markedly improved the motor and behavioral impairment caused by rotenone. Rotenone-induced histopathological changes were ameliorated by curcumin which had an additive effect to that of l-dopa or rasagiline. Conclusion: These data indicate that curcumin showed additive neuroprotective effects to L-dopa or rasagiline and ameliorated neurodegeneration, DNA fragmentation, and motor defects caused by rotenone in mice.

Assessing the interaction between L-dopa and γ-transcranial alternating current stimulation effects on primary motor cortex plasticity in Parkinson's disease.

L-dopa variably influences transcranial magnetic stimulation (TMS) parameters of motor cortex (M1) excitability and plasticity in Parkinson's disease (PD). In patients OFF dopaminergic medication, impaired M1 plasticity and defective GABA-A-ergic inhibition can be restored by boosting gamma (γ) oscillations via transcranial alternating current stimulation (tACS) during intermittent theta-burst stimulation (iTBS). However, it is unknown whether L-dopa modifies the beneficial effects of iTBS-γ-tACS on M1 in PD. In this study, a PD patients group underwent combined iTBS-γ-tACS and iTBS-sham-tACS, each performed both OFF and ON dopaminergic therapy (four sessions in total). Motor evoked potentials (MEPs) elicited by single TMS pulses and short-interval intracortical inhibition (SICI) were assessed before and after iTBS-tACS. We also evaluated possible SICI changes during γ-tACS delivered alone in OFF and ON conditions. The amplitude of MEP elicited by single TMS pulses and the degree of SICI inhibition significantly increased after iTBS-γ-tACS. The amount of change produced by iTBS-γ-tACS was similar in patients OFF and ON therapy. Finally, γ-tACS (delivered alone) modulated SICI during stimulation and this effect did not depend on the dopaminergic condition of patients. In conclusion, boosting cortical γ oscillatory activity via tACS during iTBS improved M1 plasticity and enhanced GABA-A-ergic transmission in PD patients to the same extent regardless of dopaminergic state. These results suggest a lack of interaction between L-dopa and γ-tACS effects at the M1 level. The possible neural substrate underlying iTBS-γ tACS effects, that is, γ-resonant GABA-A-ergic interneurons activity, may explain our findings.

Self-Sufficient In Vitro Multi-Enzyme Cascade for Efficient Synthesis of Danshensu from l-DOPA.

Danshensu (DSS), a traditional Chinese medicine, is widely used for the treatment of cardiovascular and cancer diseases. Here, a one-pot multi-enzyme cascade pathway was designed for DSS synthesis from l-DOPA using tyrosine aminotransferase from Escherichia coli (EcTyrB) and d-isomer-specific 2-hydroxyacid dehydrogenase from Lactobacillus frumenti (LfD2-HDH). Glutamate dehydrogenase from Clostridium difficile (CdgluD) was also introduced for a self-sufficient system of α-ketoglutaric acid and NADH. Under optimal conditions (35 °C, pH 7.0, EcTyrB:LfD2-HDH:CdgluD = 3:2:1, glutamate:NAD+ = 1:1), 98.3% yield (at 20 mM l-DOPA) and space-time yield of 6.61 g L-1 h-1 (at 40 mM l-DOPA) were achieved. Decreased yields of DSS at elevated l-DOPA concentrations (100 mM) could be attributed to an inhibited CdgluD activity caused by NH4+ accumulation. This developed multi-enzyme cascade pathway (including EcTyrB, LfD2-HDH, and CdgluD) provides an efficient and sustainable approach for the production of DSS from l-DOPA.

Evaluating Water bitter leaf (Struchium sparganophora) and Scent Leaf (Ocimum gratissimum) extracts as sources of nutraceuticals against manganese-induced toxicity in fruit fly model.

Tropical vegetables remain one of the major sources of functional foods and nutraceuticals, while their constituent phytochemicals, especially alkaloids, have been reported to exhibit neuroprotective properties. Here, the protective effect of alkaloid extracts from Scent leaf (Ocimum gratissimum) and Water bitter leaf (Struchium sparganophora) on manganese (Mn)- induced toxicity in wild type fruit fly (Drosophila melanogaster) model was investigated. Flies were exposed to 30 mM of Mn, the alkaloid extracts (20 and 200 µg/g) and co-treatment of Mn plus extracts, respectively. The survival rate and locomotor performance of the flies were assessed 7 days post-treatment, after which the flies were homogenized and assayed for activities of acetylcholinesterase (AChE), monoamine oxidase (MAO), glutathione-S transferase (GST), catalase, superoxide dismutase SOD), as well as total thiol, reactive oxygen species (ROS) and neural L-DOPA levels. Results showed that the extract significantly reversed Mn-induced reduction in the survival rate and locomotor performance of the flies. Furthermore, both extracts counteracted the Mn-induced elevation in AChE and MAO activities, as well as reduced antioxidant enzyme activities, with a concomitant mitigation of Mn-induced elevated ROS and neural L-DOPA level. The HPLC characterization of the extracts revealed the presence of N-propylamine, Vernomine and Piperidine as predominant in Water bitter leaf extract, while 2, 6-dimethylpyrazine and sesbanimide were found in scent leaf extract. Therefore, the alkaloid extract of these leaves may thus be sources of useful nutraceuticals for the management of pathological conditions associated with manganese toxicity.

Protective effects of Thai Mucuna pruriens (L.) DC. var. pruriens seeds on sexual behaviors and essential reproductive markers in chronic unpredictable mild stress mice.

Background and aims: Chronic stress is a major common cause of male infertility. Many species of velvet beans are shown to be rich in l-DOPA. In Thai folklore medicine, seeds of Mucuna pruriens (L.) DC. var. pruriens (Thai Mhamui or T-MP) have been used for treating erectile dysfunction. This study aimed to determine l-DOPA levels in T-MP seed extract and investigate its preventive on sexual behaviors and reproductive parameter damages including essential proteins in chronic unpredictable mild stress (CUMS) mice. Experimental procedure: Mice were divided into 4 groups: (I) control, (II) CUMS, (III) T-MP300 + CUMS, and (IV) T-MP600 + CUMS. Groups I and II received DW while groups III and IV were pretreated with the seed extracts (300 and 600 mg/kg BW) for 14 consecutive days before co-treatment with a randomly different CUMS/day (from 12 mild stressors) for 43 days. Results and conclusion: T-MP seed extract contained l-DOPA approximately 10% of total dried weight. A dose of 600 mg/kg improved sexual performances and degenerative seminiferous epithelium in CUMS mice. Sperm qualities and testosterone level were elevated while corticosterone was decreased in co-treatment groups. T-MP-CUMS cotreated groups also improved expressions of AKAP4, AR, and TyrPho proteins in testis, epididymis, and sperm. T-MP increased StAR and CYP11A1 expressions in testis. It also suppressed testicular apoptosis via decreased expressions of Hsp70, caspases 3, and 9. T-MP seeds containing l-DOPA could improve sexual behaviors and essential reproductive proteins caused by CUMS. Section: Natural Products. Taxonomy classification by evise: Traditional Herbal Medicine; Animal Model; Histopathology.

Biodegradable Nanoparticles Loaded with Levodopa and Curcumin for Treatment of Parkinson's Disease.

Background: Parkinson's disease (PD) is the second most common age-related neurodegenerative disorder. Levodopa (L-DOPA) remains the gold-standard drug available for treating PD. Curcumin has many pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, anti-amyloid, and antitumor properties. Copolymers composed of Poly (ethylene oxide) (PEO) and biodegradable polyesters such as Poly (ε-caprolactone) (PCL) can self-assemble into nanoparticles (NPs). This study describes the development of NH2-PEO-PCL diblock copolymer positively charged and modified by adding glutathione (GSH) on the outer surface, resulting in a synergistic delivery of L-DOPA curcumin that would be able to pass the blood-brain barrier. Methods: The NH2-PEO-PCL NPs suspensions were prepared by using a nanoprecipitation and solvent displacement method and coated with GSH. NPs were submitted to characterization assays. In order to ensure the bioavailability, Vero and PC12 cells were treated with various concentrations of the loaded and unloaded NPs to observe cytotoxicity. Results: NPs have successfully loaded L-DOPA and curcumin and were stable after freeze-drying, indicating advancing into in vitro toxicity testing. Vero and PC12 cells that were treated up to 72 h with various concentrations of L-DOPA and curcumin-loaded NP maintained high viability percentage, indicating that the NPs are biocompatible. Conclusions: NPs consisting of NH2-PEO-PCL were characterized as potential formulations for brain delivery of L-DOPA and curcumin. The results also indicate that the developed biodegradable nanomicelles that were blood compatible presented low cytotoxicity.

Mucuna pruriens Seed Aqueous Extract Improved Neuroprotective and Acetylcholinesterase Inhibitory Effects Compared with Synthetic L-Dopa.

L-dopa, a dopaminergic agonist, is the gold standard for the treatment of Parkinson's disease. However, due to the long-term toxicity and adverse effects of using L-dopa as the first-line therapy for Parkinson's disease, a search for alternative medications is an important current challenge. Traditional Ayurvedic medicine has suggested the use of Mucuna pruriens Linn. (Fabaceae) as an anti-Parkinson's agent. The present study aimed to quantify the amount of L-dopa in M. pruriens seed extract by HPLC analysis. The cytotoxicity and neuroprotective properties of M. pruriens aqueous extract were investigated by two in vitro models including the serum deprivation method and co-administration of hydrogen peroxide assay. The results showed the significant neuroprotective activities of M. pruriens seed extracts at a concentration of 10 ng/mL. In addition, the effects of L-dopa and M. pruriens seed extract on in vitro acetylcholinesterase activities were studied. M. pruriens seed extract demonstrated acetylcholinesterase inhibitory activity, while synthetic L-dopa enhanced the activity of the enzyme. It can be concluded that the administration of M. pruriens seed might be effective in protecting the brain against neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. M. prurience seed extract containing L-dopa has shown less acetylcholinesterase activity stimulation compared with L-dopa, suggesting that the extract might have a superior benefit for use in the treatment of Parkinson's disease.

Seed extract of Thai Mucuna pruriens (L.) DC. var. pruriens enhances sexual performance and improves male reproductive damages in ethanol-induced rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Thai Mucuna pruriens (L.) DC. var. pruriens (T-MP) has been traditionally used in treating depressive disorders, dysuria and enhancing male sexual desire. Although T-MP seed is demonstrated to have antioxidant capacity, its aphrodisiac and protective tissue damage properties have never been documented. Recently, ethanol (Eth) is known to cause sexual behavior dysfunction and damage reproductive system. This study aimed to investigate the protective effects of T-MP seed extract on sexual behavior dysfunction and reproductive damages in male rats admisted with Eth. MATERIALS AND METHODS: T-MP possessing antioxidant activity was determined for L-DOPA content using NMR analysis. Thirty-six male rats were divided into four groups (9 animals/group). Control rats received DW and the ethanol (Eth) group was given with Eth (3 g/kgBW; 40%v/v). In preventive groups (T-MP150 + Eth and MP300 + Eth groups), animals were treated with T-MP extract at a dose of 150 and 300 mg/kgBW before Eth administration for consecutive 56 days. Sexual behaviors including mounting frequency (MF), intromission frequency (IF), mounting latency (ML), intromission latency (IL), ejaculation latency (EL), post-ejaculatory interval (PEI), and ejaculation frequency (EF) were evaluated. Epididymal sperm quality and daily sperm production (DSP) were examined. Testicular histology was observed using Masson's trichrome staining. The malondialdehyde (MDA) levels and expressions of androgen receptor (AR), heat shock protein 70 (HSP70), steroidogenic acute regulatory (StAR), and tyrosine-phosphorylated (TyrPho) proteins in testis were also determined. RESULTS: T-MP extract contained L-DOPA and improved sexual behaviors including increased MF and IF and decreased ML and IL in Eth treated rats. Significantly, sperm quality, DSP, and testicular histopathology observed in Eth group were improved after T-MP treatment. T-MP also decreased the testicular MDA levels. Additionally, T-MP could correct testicular functional proteins of AR and StAR except HSP70 expression in Eth group. Expressions of TyrPho proteins in testicular and sperm lysates were improved in co-administered groups. CONCLUSIONS: T-MP seed extract possessing L-DOPA could enhance the sexual behaviors and protect reproductive damages via improvement of testicular functional proteins.

Development of Prodrugs for Treatment of Parkinson's Disease: New Inorganic Scaffolds for Blood-Brain Barrier Permeation.

The treatment of Parkinson's disease (PD) has not been consistently modified for more than 60 years. L-DOPA, the blood-brain barrier permeable precursor prodrug of dopamine, is to date the only effective therapy on the market. However, it is well known that prolonged treatment with L-DOPA leads to several side effects, which may affect the patient's life expectancy (i.e., the wearing-off phenomenon, on-off fluctuations, and dyskinesia). For this reason, modifications, and supplements to L-DOPA treatment have been and are being studied, which, however, have not yet resulted in a valid alternative to the cornerstone drug. This review aims to summarize the main formulations currently in use for PD treatment, explaining advantages and disadvantages for each class. The attention will be focused on the promising prodrug concept, aimed at finding a suitable L-DOPA substitute with improved pharmacokinetic behavior. In this respect, new potential candidates which show interesting properties for the intended scope, the so-called dicarba-closo-dodecaboranes(12) (carboranes), will be discussed. Carboranes are inorganic molecular icosahedral boron-carbon clusters with 12 vertices and 20 deltahedral faces. They have been extensively studied for applications in medicine as potential pharmacophores, reagents in boron neutron capture therapy (BNCT) and radiotherapy. Here, we discuss them as inorganic scaffolds for dopamine delivery at the central nervous system (CNS) level.

Experimental validation of Vitex negundo leaves hydroalcoholic extract for neuroprotection in haloperidol induced parkinson's disease in rat.

Parkinsonism is a neurodegenerative disease, mainly imbalance in dopamine and acetylcholine neurotransimitter in mid brain, which manifestation of dysfunctions of extrapyramidal like akinesia, tremor, rigidity and catalepsy etc., even cognitive and memory loss. The current study is framed to evaluate the effect of Vitex negundo (VNL) leaf extract in Haloperidol induced PD in rats. In vitro studies of antioxidant capacity were checked via DPPH and NO assays and identified its Acetylcholinesterase (AChE) inhibitory activity. Secondly the In vivo study of anti-PD activity in Haloperidol induced in rats were evaluated by Rotarod, morris water maze (MWM), cooks pole climb (CPC), actophotometer, novel object recognition (NOR), and T-maze were utilized to assess extrapyramidal, cognitive and memory function. Thirdly, changes in biomarker level viz. (AChE), butyrylcholinesterase. (BChE) in hippocampus and cortex, reduced glutathione (GSH), malondialdehyde (MDA), total protein (TP), superoxide dismutase (SOD), catalase (CAT), and dopamine level in the whole brain were measured. Finally, histopathology of hippocampus and cortex was examined at 40x magnification to access restoring integrity and maintaining the architecture of neuronal cell in the treatment group compared to control group and L-DOPA as a standard treatment group. V. negundo showed potent antioxidant potency on scavenging of DPPH (IC50 84.81 µg/ml) and NO (IC50 133.20 µg/ml) and possess AChE inhibitory potency (IC50 114.35 µg/ml) by in vitro studies. The Rotarod, MWM, CPC, Actophotometer, NOR, T-maze demonstrated that Haloperidol group administration declines performance time, ELT, TL and decreases locomotion, cognitive and memory respectively. The treatment of VNL 100, 200, and 400 mg/kg p.o. significantly (p < 0.05 to p < 0.0001) reversed. Whole brain AChE, BChE, and MDA level were significantly raised and GSH, TP, SOD, CAT and Dopamine were significantly declined in Haloperidol treated group rats, especially V. negundo 400 mg/kg p.o. highly significantly ameliorate the Haloperidol group altered pathological changes through the restoration of the cholinergic function, enhancing the antioxidant defense and by increasing the dopaminergic function. The current study provides validation of V. negundo for its anti-PD activity and could be a valuable source for the treatment of PD in future.

Effect of catechin and commercial preparation of green tea essence on the pharmacokinetics of l-dopa in rabbits.

The aim of this study was to investigate drug interactions of L-dopa/carbidopa with catechin and green tea essence in rabbits following the simultaneous administration via an intramuscular injection of catechin or via an intragastric route for green tea essence with L-dopa/carbidopa. The results indicated that catechin at doses of 10, 20 and 50 mg/kg increased the area under the plasma concentration-time curve from time zero to the time of the last quantifiable concentration (AUC0-t ) of L-dopa by about 69, 78 and 42%, respectively. The metabolic ratios of the AUC0-t for 3-O-methyldopa (3-OMD)/L-dopa significantly decreased by about 56, 68 and 76% (P < 0.05), respectively. In addition, a single dose of 5/1.25 mg/kg L-dopa/carbidopa was co-administrated with 150 mg/kg green tea essence via an intragastric route with an oral-gastric tube. Comparing the related pharmacokinetic parameters of L-dopa, the clearance and metabolic ratio of L-dopa decreased by 20 and 19% (P < 0.05), respectively. In conclusion, catechin and green tea essence can significantly affect the metabolism of L-dopa by the catechol-O-methyltransferase (COMT) metabolic pathway. Catechin can enhance L-dopa bioavailability, and both catechin and green tea essence decreased 3-OMD formation. Therefore, catechin and green tea essence may increase L-dopa efficacy for Parkinson's disease treatment.

Tetrahydrobiopterin deficiencies: Lesson from clinical experience.

OBJECTIVES: The present study describes clinical, biochemical, molecular genetic data, current treatment strategies and follow-up in nine patients with tetrahydrobiopterin (BH4) deficiency due to various inherited genetic defects. METHODS: We analyzed clinical, biochemical, and molecular data of nine patients with suspected BH4 deficiency. All patients were diagnosed at Ege University Faculty of Medicine in Izmir, Turkey and comprised data collected from 2006 to 2019. The diagnostic laboratory examinations included blood phenylalanine and urinary or plasma pterins, dihydropteridine reductase (DHPR) enzyme activity measurement in dried blood spots, folic acid and monoamine neurotransmitter metabolites in cerebrospinal fluid, as well as DNA sequencing. RESULTS: Among the nine patients, we identified one with autosomal recessive GTP cyclohydrolase I (ar GTPCH) deficiency, two with 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency, three with sepiapterin reductase (SR) deficiency, and three with DHPR deficiency. Similar to previous observations, the most common clinical symptoms are developmental delay, intellectual disability, and movement disorders. All patients received treatment with l-dopa and 5-hydroxytryptophan, while only the ar GTPCH, the PTPS, and one DHPR deficient patients were supplemented in addition with BH4. The recommended dose range varies among patients and depends on the type of disease. The consequences of BH4 deficiencies are quite variable; however, early diagnosis and treatment will improve outcomes. CONCLUSIONS: As BH4 deficiencies are rare group of treatable neurometabolic disorders, it is essential to diagnose the underlying (genetic) defect in newborns with hyperphenylalaninemia. Irreversible brain damage and progressive neurological deterioration may occur in untreated or late diagnosed patients. Prognosis could be satisfying in the cases with early diagnose and treatment.

Anterior pituitary gland synthesises dopamine from l-3,4-dihydroxyphenylalanine (l-dopa).

Prolactin (PRL) is a hormone principally secreted by lactotrophs of the anterior pituitary gland. Although the synthesis and exocytosis of this hormone are mainly under the regulation of hypothalamic dopamine (DA), the possibility that the anterior pituitary synthesises this catecholamine remains unclear. The present study aimed to determine if the anterior pituitary produces DA from the precursor l-3,4-dihydroxyphenylalanine (l-dopa). Accordingly, we investigated the expression of aromatic l-amino acid decarboxylase (AADC) enzyme and the transporter vesicular monoamine transporter 2 (VMAT2) in the anterior pituitary, AtT20 and GH3 cells by immunofluorescence and western blotting. Moreover, we investigated the production of DA from l-dopa and its release in vitro. Then, we explored the effects of l-dopa with respect to the secretion of PRL from anterior pituitary fragments. We observed that the anterior pituitary, AtT20 and GH3 cells express both AADC and VMAT2. Next, we detected an increase in DA content after anterior pituitary fragments were incubated with l-dopa. Also, the presence of l-dopa increased DA levels in incubation media and reduced PRL secretion. Likewise, the content of cellular DA increased after AtT20 cells were incubated with l-dopa. In addition, l-dopa reduced corticotrophin-releasing hormone-stimulated adrenocorticotrophic hormone release from these cells after AADC activity was inhibited by NSD-1015. Moreover, DA formation from l-dopa increased apoptosis and decreased proliferation. However, in the presence of NSD-1015, l-dopa decreased apoptosis and increased proliferation rates. These results suggest that the anterior pituitary synthesises DA from l-dopa by AADC and this catecholamine can be released from this gland contributing to the control of PRL secretion. In addition, our results suggest that l-dopa exerts direct actions independently from its metabolisation to DA.

Acute and Chronic Dopaminergic Depletion Differently Affect Motor Thalamic Function.

The motor thalamus (MTh) plays a crucial role in the basal ganglia (BG)-cortical loop in motor information codification. Despite this, there is limited evidence of MTh functionality in normal and Parkinsonian conditions. To shed light on the functional properties of the MTh, we examined the effects of acute and chronic dopamine (DA) depletion on the neuronal firing of MTh neurons, cortical/MTh interplay and MTh extracellular concentrations of glutamate (GLU) and gamma-aminobutyric acid (GABA) in two states of DA depletion: acute depletion induced by the tetrodotoxin (TTX) and chronic denervation obtained by 6-hydroxydopamine (6-OHDA), both infused into the medial forebrain bundle (MFB) in anesthetized rats. The acute TTX DA depletion caused a clear-cut reduction in MTh neuronal activity without changes in burst content, whereas the chronic 6-OHDA depletion did not modify the firing rate but increased the burst firing. The phase correlation analysis underscored that the 6-OHDA chronic DA depletion affected the MTh-cortical activity coupling compared to the acute TTX-induced DA depletion state. The TTX acute DA depletion caused a clear-cut increase of the MTh GABA concentration and no change of GLU levels. On the other hand, the 6-OHDA-induced chronic DA depletion led to a significant reduction of local GABA and an increase of GLU levels in the MTh. These data show that MTh is affected by DA depletion and support the hypothesis that a rebalancing of MTh in the chronic condition counterbalances the profound alteration arising after acute DA depletion state.

In vitro spectroscopic investigation of groove binding interaction of Fe3O4@CaAl-LDH@L-Dopa with calf thymus DNA.

The principal goal of this study is to evaluate the interaction of Fe3O4@CaAl-LDH@L-Dopa and Fe3O4@CaAl-LDH nanoparticles with calf thymus DNA. The magnetic nanoparticles were previously prepared by a chemical co-precipitation method, and the surface of the Fe3O4 nanoparticles was coated with CaAl layered double hydroxides. The antiparkinsonian drug "L-Dopa" was carried by this core-shell nanostructure to achieve the drug delivery system with suitable properties for biological applications. Also, the interaction of Fe3O4@CaAl-LDH@L-Dopa and Fe3O4@CaAl-LDH nanoparticles with CT-DNA was studied using, UV-Visible spectroscopy, viscosity, circular dichroism (CD), and fluorescence spectroscopy techniques. The results of investigations demonstrated that Fe3O4@CaAl-LDH@L-Dopa and Fe3O4@CaAl-LDH nanoparticles have interacted via minor groove binding and intercalated to CT-DNA, respectively.